From: Andrew Lunn <andrew@lunn.ch>
To: Antoine Tenart <antoine.tenart@bootlin.com>
Cc: davem@davemloft.net, f.fainelli@gmail.com, hkallweit1@gmail.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v3 2/2] net: phy: mscc: RGMII skew delay configuration
Date: Thu, 19 Mar 2020 17:05:05 +0100 [thread overview]
Message-ID: <20200319160505.GE27807@lunn.ch> (raw)
In-Reply-To: <20200319141958.383626-3-antoine.tenart@bootlin.com>
On Thu, Mar 19, 2020 at 03:19:58PM +0100, Antoine Tenart wrote:
> This patch adds support for configuring the RGMII skew delays in Rx and
> Tx. The Rx and Tx skews are set based on the interface mode. By default
> their configuration is set to the default value in hardware (0.2ns);
> this means the driver do not rely anymore on the bootloader
> configuration.
>
> Then based on the interface mode being used, a 2ns delay is added:
> - RGMII_ID adds it for both Rx and Tx.
> - RGMII_RXID adds it for Rx.
> - RGMII_TXID adds it for Tx.
>
> Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
> ---
> drivers/net/phy/mscc/mscc.h | 14 ++++++++++++++
> drivers/net/phy/mscc/mscc_main.c | 29 +++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+)
>
> diff --git a/drivers/net/phy/mscc/mscc.h b/drivers/net/phy/mscc/mscc.h
> index d1b8bbe8acca..25729302714c 100644
> --- a/drivers/net/phy/mscc/mscc.h
> +++ b/drivers/net/phy/mscc/mscc.h
> @@ -161,6 +161,20 @@ enum rgmii_rx_clock_delay {
> /* Extended Page 2 Registers */
> #define MSCC_PHY_CU_PMD_TX_CNTL 16
>
> +#define MSCC_PHY_RGMII_SETTINGS 18
> +#define RGMII_SKEW_RX_POS 1
> +#define RGMII_SKEW_TX_POS 4
> +
> +/* RGMII skew values, in ns */
> +#define VSC8584_RGMII_SKEW_0_2 0
> +#define VSC8584_RGMII_SKEW_0_8 1
> +#define VSC8584_RGMII_SKEW_1_1 2
> +#define VSC8584_RGMII_SKEW_1_7 3
> +#define VSC8584_RGMII_SKEW_2_0 4
> +#define VSC8584_RGMII_SKEW_2_3 5
> +#define VSC8584_RGMII_SKEW_2_6 6
> +#define VSC8584_RGMII_SKEW_3_4 7
> +static void vsc8584_rgmii_set_skews(struct phy_device *phydev)
> +{
> + u32 skew_rx, skew_tx;
> +
> + /* We first set the Rx and Tx skews to their default value in h/w
> + * (0.2 ns).
> + */
> + skew_rx = VSC8584_RGMII_SKEW_0_2;
> + skew_tx = VSC8584_RGMII_SKEW_0_2;
Hi Antoine
Does this mean it is impossible to have a skew of 0ns?
Andrew
next prev parent reply other threads:[~2020-03-19 16:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-19 14:19 [PATCH net-next v3 0/2] net: phy: mscc: add support for RGMII MAC mode Antoine Tenart
2020-03-19 14:19 ` [PATCH net-next v3 1/2] " Antoine Tenart
2020-03-19 15:58 ` Andrew Lunn
2020-03-19 14:19 ` [PATCH net-next v3 2/2] net: phy: mscc: RGMII skew delay configuration Antoine Tenart
2020-03-19 16:05 ` Andrew Lunn [this message]
2020-03-19 16:17 ` Antoine Tenart
2020-03-19 16:52 ` Andrew Lunn
2020-03-20 4:15 ` [PATCH net-next v3 0/2] net: phy: mscc: add support for RGMII MAC mode David Miller
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